[PATCH] x86 execve from kernel

[Brian Gerst]

Remove the jump through int $0x80 for execve from a kernel thread.

--
				Brian Gerst
diff -urN linux-bk/arch/i386/kernel/process.c linux/arch/i386/kernel/process.c
--- linux-bk/arch/i386/kernel/process.c	2004-03-14 18:25:39.000000000 -0500
+++ linux/arch/i386/kernel/process.c	2004-03-14 19:39:47.333293016 -0500
@@ -630,6 +630,33 @@
 }
 
 /*
+ * execs a userspace program from a kernel thread
+ */
+int execve(char *filename, char **argv, char **envp)
+{
+	struct pt_regs regs;
+	int error;
+	unsigned long flags;
+
+	memset(&regs, 0, sizeof(regs));
+	regs.eflags = X86_EFLAGS_IF;
+
+	error = do_execve(filename,
+			(char __user * __user *) argv,
+			(char __user * __user *) envp,
+			&regs);
+	if (error == 0) {
+		current->ptrace &= ~PT_DTRACE;
+		__asm__ __volatile__(
+		       "movl %0,%%esp\n\t"
+		       "movl %1,%%ebp\n\t"
+		       "jmp resume_userspace\n\t"
+		       : : "r" (&regs), "r" (current_thread_info()));
+	}
+	return error;
+}
+
+/*
  * These bracket the sleeping functions..
  */
 extern void scheduling_functions_start_here(void);
diff -urN linux-bk/include/asm-i386/unistd.h linux/include/asm-i386/unistd.h
--- linux-bk/include/asm-i386/unistd.h	2004-03-14 18:25:46.000000000 -0500
+++ linux/include/asm-i386/unistd.h	2004-03-14 19:12:38.000000000 -0500
@@ -395,7 +395,7 @@
 static inline _syscall3(int,read,int,fd,char *,buf,off_t,count)
 static inline _syscall3(off_t,lseek,int,fd,off_t,offset,int,count)
 static inline _syscall1(int,dup,int,fd)
-static inline _syscall3(int,execve,const char *,file,char **,argv,char **,envp)
+extern int execve(char *, char **, char **);
 static inline _syscall3(int,open,const char *,file,int,flag,int,mode)
 static inline _syscall1(int,close,int,fd)
 static inline _syscall3(pid_t,waitpid,pid_t,pid,int *,wait_stat,int,options)